9 month old self weaning?

Please help me if anybody has gone through this after a great supply for 8.5 months. I recently made a post maybe tuesday that my almost 9 month old is not following his growth chart, and my ped told me I dont know what I’m doing bc I breastfeed on demand (hes always been content with the breast, and if I ever saw him not content after I would

Top off with my hand expressed milk/it happened maybe 20 times so not that many he eas always efficient at the breast) and he has 3 solid meals a day with one snack in the afternoon as well. Well after that appt I started topping off with my hand expressed milk that I would do right after I fed him…. At first he would chug the milk ( we do a syringe, he just plays with the bottle). Well today is now almost Monday (so almost a whole week has gone by) and on Sunday has been such a hard, sad day for me. My baby literally only took a full feeding in the morning, and then I was having to beg him to feed off of me, his naps were both shitty, he was fussy like he was hungry so I kept topping it off with hand expressing, and then it got to a point in the afternoon where I started pumping to replace the feed my son is refusing on me (saturday was rough too, with him only eating maybe 3 mins at a time and that was it, acting still hungry afterwards) . When I pumped I DIDNT EVEN GET ONE OUNCE. Not even between both breasts. This was at 4 pm. Now I’m curious if my baby boy is self weaning, bevause I dont have as much milk anymore? Tye poor thing was hungry. I could tell. And my breasts were so empty,a and I wasnt empty, ever before this week.I am at a loss. I dont want to stop breastfeeding. Its hard but I never saw this coming, its way too soon for me, he is not even 9 months old until the 18th. I am heartbroken. I dont know what to do to get him to latch longer. And now I guess hes starting to sleep A little longer at night, so tonight I just woke him up to feed, bc I dont know anymore if my supply will be Able to handle him not feeding in the day and now AND at night. He used to wake up much more to feed at night. Please any advice what I need to do to keep breastfeeding. I will start pumping if he doesn’t feed because otherwise my supply will dry up im assuming? On top of it my son hasnt been following his growth chart. So I am so so beyond stressed and worried.

EDIT: I am at a point where I want to go buy him formula. I want him to just be fed, and content, even if its not from me. I am so sad, to know that he is hungry in the day, I dont want that. I feel horrible, sad, heartbroken. Idk what happened. Idk where it all went wrong we were fine and then thursday and friday were a bit rough but saturday and sunday I feel like he almost even didnt eat off of me at all…his wet diapers have decresead at least by 4 less wet full diapers. Its not like him, he poops after every solid meal so I expect him to feed off of me after but he’s just not interested at all yesterday and that is so comcerning for me to the point I tried to force him but its like there is nothing coming out either so I cant blame him….At nighttime my breasts arent getting full like before, its so weird. I am just sitting here crying at 3 am. I feel like a failure and a horrible mother. Maybe I was unlatching him too soon… maybe I have been too stressed bc me and his dad argued and I havent even been sleeping bc of if…I have been so so anxious. Maybe he can feel me. Please please help me what do I do to keep my breastfeeding journey.

UPDATE: he is doing better at the breast and now we’re doing 3x a day solids but only until he tells me he is full, no desserts for every meal etc. And hes been at the breast less than every 3 hrs ( he literally did cluster feed)

One thing I’m worried about is if I’m making enough milk for him… he is still having not too many wet diapers at all… what do I do? Do I wait until the end of the week to see how this is going and maybe if not I can contact a lactation consultant to come and help me out to combo feed maybe? As long as my baby is gaining weight as he should be I wont be as worried… he is not follow his growth curve and I’m sure this is only making him lose weight and not gain any…. And right now I NEED him to gain more than anything… I know babies need to gain a certain weight per week so…i wish he would take a bottle too